A wide variety of pole-mounting systems and structures have been used to anchor poles and to provide support against wind loads and the like. These structures and systems have been used for light poles, flag poles, traffic signal supports, highway sign posts, telephone and electricity poles and a variety of other support poles.
Such poles are often very long and encounter great wind loads and other stresses. A common type of pole-mounting system utilizes a pole which is hollow, rectangular (e.g., square) in cross-section and includes a base support (or “plate”) to which the lower end of the pole is welded or otherwise affixed. The base support may have bolt holes by which it is attached to bolts set in concrete, although other ground-attachment means may be used. Some pole-mounting systems use a variety of other structures for providing support for the poles. Various structures have been used in supporting each of the above-mentioned product types, and typically involve interconnection of a pole and a base support by welding and/or bolts.
Particular regions of concern when it comes to the strength and endurance of poles of various kinds include hand-hole areas—i.e., the areas typically near the pole bottoms used to facilitate wiring of fixtures—and any areas involving joints or juncture points or lines. Pole failures can be related to such things, making the nature of the structures of particular importance.
A particularly significant improvement in the strength of such poles is the invention disclosed in U.S. Pat. No. 6,640,517 (Mitchell), assigned to Ruud Lighting, Inc. of Racine, Wis. Such document is incorporated herein by reference. As noted in such patent, the Mitchell invention provides significant increases in pole strength and endurance. Increasing pole strength and endurance against wind forces and the like, and maintaining excellent pole strength and endurance (or even increasing them) while reducing material usage and consumer cost continue to be important industry objectives. Indeed, preferred forms of the invention described in this document are improvements of the prior Mitchell invention.
Despite improvements in the past, there remains a need for enhancement in pole strength, endurance and resistance to failure. And, there remains a need for these things to be achieved while minimizing material usage and cost and while retaining efficiency in manufacture and assembly.